丙戊酸联合替西罗莫司抑制弥漫大B细胞淋巴瘤细胞生长的机制研究

Mechanism of Inhibiting the Cell Growth in Diffuse Large B-cell Lymphoma by Valproic Acid Combined with Temsirolimus

本研究探讨联合应用短链脂肪酸类去乙酰化酶(HDAC)抑制剂丙戊酸(VPA)和哺乳动物雷帕霉素靶蛋白(mTOR)抑制剂替西罗莫司(TEM)抑制弥漫大B淋巴瘤细胞生长的机制。应用MTT法检测细胞增殖抑制率,瑞氏染色检测细胞形态学改变,流式细胞术检测细胞凋亡、周期及自噬相关蛋白,透射电子显微镜检测细胞超微结构变化,蛋白质印迹法检测相关蛋白水平。结果表明,单用VPA和TEM均可抑制淋巴瘤细胞增殖,两药合用抑制作用更为显著;流式细胞术检测结果显示,两药联合后可阻断细胞周期,引起自噬相关蛋白LC3表达增高;电子显微镜检测进一步证实,经VPA及TEM处理后的细胞出现自噬体和自噬溶酶体,两药合用时自噬现象更为显著;蛋白质免疫印迹证实,自噬通路相关蛋白的表达发生改变;经VPA处理后HDAC1和HDAC3表达下调,组蛋白乙酰化水平升高,表明VPA可通过表观遗传学调控影响淋巴瘤细胞增殖、促进其自噬。结论:VPA和TEM在阻断淋巴瘤细胞增殖、促进细胞自噬方面具有协同效应,为药物联合治疗提供了新的理论基础,具有良好的临床应用前景。

The aim of this study was to illustrate the mechanism of inhibiting the cell growth in diffuse large B-cell lymphoma by histone deacetylase inhibitor valproic acid （VPA） combined with mTOR inhibitor temsirolimus （TEM）. MTT assay and Wright＇s stain were used to assess cell growth inhibition and to detect the cell morphological changes re- spectively. The cell apoptosis, cell cycle and cell autophagy were determined by flow cytometry. Ultrastructttre changes were confirmed by electron microscopy. Protein changes were detected by Western blot. The results showed that both VPA and TEM alone inhibited cell proliferation and the effect was more obvious in the combination group. VPA com- bined with TEM induced cell arrest in G0/G1 phase and upregulated the expression of autophagy-related protein LC3, without cell apoptosis. Moreover, typical autophagosomes were observed, further confirming the presence of autophagy. Western blot showed the changes of proteins involved in autophagy signaling pathway. VPA decreased HDAC1 and HDAC3 expression and increased histone acetylation, suggesting that VPA also affected lymphoma cell proliferation through epigenetic modification. It is concluded that the combined treatment of VPA and TEM induces cell cycle arrest and cell autophagy, which provides a new clue for their clinical application in diffuse large B-cell lymphoma.